The middle manager's time is a lot less expensive in most cases.
In upper management it might be one very senior “right hand.” In the lower tranches of middle management there will be more and more hands-on technical-track leaders.
But as you pointed out, it's necessary otherwise everyone has to deal with the bullshit.
VP 1: “Jason? He is still there? How?”
VP 2: “He never managed anyone.”
I thought about that a lot. What is it about being middle management that is so lethal? Its exactly as you said: Liabilities from from above, below and sideways.
Why would anyone ever sign up for that?
What would a middle manager need to teach me? Genuinely curious, as a person that enjoys learning, and have been doing it on my own for awhile.